Classification & Evolution Flashcards
What is taxonomy?
Practice of biological classification
What is hierarchical classification? What are the groups?
used to organise and group similar organisms together
DOMAIN
KINGDOM
PHYLUM
CLASS
ORDER
FAMILY
GENUS
SPECIES
Why are binomial names important? What do they consist of/who developed this naming system?
They allow for the species to be universally identified
Carl Linnaeus created binomial system
Consist of genus and species name
What are the 3 domains?
Bacteria (prokaryotes) - no nucleus /vary in size
Archaea (prokaryotes)- smaller size range
Eukarya (eukaryotes) - nuclei and membrane bound organelle
- vary in size
- 80S ribosomes/linear DNA
Difference between archaea and bacteria ?
Archaea have :
Unique membrane lipids
Ribosomal DNA - *base sequence of rRNA more similar to that in eukarya than bacteria
- primary structure of ribosome proteins in archaea more similar to proteins in eukarya
Composition of cell wall - cell wall dont contain peptidoglycan
Have histones
What are the 5 kingdoms?
Prokaryota - no nucleus/mitochondria
- unicellular
Domain : eukarya
Protoctista - mostly single celled but can be multicellular , eukaryotic cells (autotrophic/heterotrophic)
Fungi- chitin cell wall/ single celled/multicellular / saprotrophic (absorb substance from dead organisms)
Plantae- multicellular, cellulose cell wall , autotrophic (produce own food)
Animalia - multicellular , no cell wall , heterotrophic (consume plants/animals)
What is homology?
Grouping organisms based on features they shared
What is phylogeny?
Evolutionary history of organisms
What are phylogenetic trees?
Diagrams to show evolutionary relationship between different taxa
What sequence data is used to investigate evolutionary relationships?
DNA - how its stored /sequence of bases
MRNA
Amino acids - sequcne of amino acids compared to
- the more similar the amino acid sequence in cytochrome C in 2 different species, the more closely related they are
For all sequence data , the more similar the sequences, the more closely related the species are. - Species that have been separated for longer have had more time for mutations in DNA,mRNA and amino acid sequences - so less closely related
What evidence does classification system use to identify how closely related organisms are?
Observable features - can’t be only thing used as scientist disagree on importance of different features
Molecular evidence- mRNA/DNA/proteins
Embryological evidence - similarities are early stage of development
Anatomical evidence - similarity in structure/fucntion of body parts
Behavioral evidence - similarity in behavior/social organisation
What is evolution?
Change in adaptive features of a population over time as a result of natural selection
Darwin’s key observations that helped develop theory of evolution?
- organisms produce more offspring than could survive
- populations of organisms fluctuate - not much
- variation in characteristics in populations of same species
- offspring inherit characteristics from parents
Evidence for the Theory of Evolution?
Fossil evidence - can tell that environments have changed significantly
- can be dated so put organisms in order from oldest to youngest and see how they changed
- show similarities between extinct species/ancestral species and species today
Molecular evidence - DNA can provide evidence for evolutionary relationships between species/how genetic code of species has changed
- more similar sequence is , more closely related it is
Those will more similar sequences will have been separated RECENTLY , than those with very different sequences
2 types of variation?
Genetic variation: variation in genotypes between species (interspecific) /within a species (intraspecific)
Phenotypic variation: variation in phenotypes between species or within species
What is discontinuous variation?
When they are 2 or more distinct categories - no intermediates
- qualitative differences in phenotype falls into this type of variation
E.g blood type, colour
What is continuous variation?
When individuals in population vary within a range - no distinct categories
- quantitative differences in phenotype causes this type of variation
E.g : mass, height, width
Causes of discontinuous variation?
Genetic factors :
Different species have different genes - effect phenotype
Individuals of same species have same genes but different versions of them (alleles)
- different alleles at a single gene locus have large effect on phenotype
Causes of continuous variation?
caused by an interaction between genetics and the environment
GENETIC:
Different alleles at a single locus have a small effect on the phenotype
ENVIRONMENT :
- changes in sunlight hours, supply of nutrients/water, temperature range , oxygen levels effect how organisms grow and develop
what are adaptations?
Features that increase its chances of survival/reproduction and the chances of offspring reproducing successfully
How do adaptations arise?
Through evolution by natural selection
Types of adaptations?
Anatomical : structural/physical features (white fur on polar bears help camouflage)
Physiological: biological processes within organisms (Mosquitos produce chemicals that stop animal’s blood clotting when they bite - feed more easily)
Behavioral : way an organism behaves (Cold-blooded reptiles bask in the sun to absorb heat)
What is convergent evolution? How does it occur?
When species don’t share a common ancestor/live in different part of world but saw high levels of similarity in terms of adaptations they possess
- occurs when 2 habitats, they have become adpated to, are similar
Process of natural selection?
Random mutation can produce new alleles of a gene
Selection pressures (environmental factors : predation/disease/competition) create struggle for survival
the new alleles may benefit their possessor, leading to an increased chance of survival and increased reproductive success
The advantageous allele is passed onto the next generation
As a result, over several generations, the new allele will increase in frequency in the population
How has antibiotics resistance arisen?
-
variations caused by mutations
Mutation may cause resistance to antibiotic - therefore bacteria survive to reproduce /pass on gene of resistance to next generation
- greater frequency of gene in population , in next generations
How to reduce antibiotic resistance?
- Only prescribing antibiotics when absolutely necessary/ not used for viral infections
- complete courses of antibiotics
- Rotate which antibiotics are used so one type is not continuously used
- use of antibiotics in agriculture reduced
- use HIGHLY SPECIFIC ANTIBIOTICS for disease
Implications of pesticide resistance in insects ?
- farmers may have to use broader pesticides which could kill beneficial insects as well as normal insects
- if insect is resistant/carrying disease, could spread disease
- new pesticides need to be produced to prevent resistance to all pesticides - COST TIME /MONEY
Reasons for antibiotic resistance arising?
overuse of antibiotics - human exert selective pressure on bacteria so support evolution of antibiotic resistance
Large scale use of antibiotics in farming
How to reduce spread of already resistant strains of bacteria?
- ensure good hygiene
- isolate infected patients
How to prevent pesticide resistance ?
Use combination of pesticides
Use other form of pest control:
BIOLOGICAL CONTROL - introduce natural parasite/predators
Use SELECTIVELY BRED CROPS/GENETICALLY MODIFIED PEST RESISTANT CROPS
How did Wallace contribute to acceptance of Darwin’s theory of evolution?
- had similar ideas to Darwin
Arrived at independently
How do scientific community make/validate new theories/discoveries?
- meetings/peer review
One cell component present in all 3 domains?
Ribosomes
Degrees of freedom formula?
V = (n1 -1) + (n2 -1)
When to reject/accept null hypothesis ?
t/ Rs < critical value = ACCEPTED - no significant difference between 2 results
If accepting H0, correlation not significant for Rs
T value/ Rs value > critical value = REJECTED
If rejecting H0, correlation is significant for Rs
When to use spearman’s rank correlation coefficient?
When data is not normally distributed - investigate possible correlation
What causes convergent evolution?
- same niche/lifestyle or habitat
- similar selection pressure
What does spearman’s rank correlation coefficient tell you about correlation?
Value near :
1 - perfect POSITIVE correlation
0 - no correlation
-1 - perfect NEGATIVE CORRELATION
